Transmitter



H. s. MARSH 1,795,341

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Patented Mar. 10, 1931 UNITED STATES PATENT OFFICE HARRY S. MARSH, OF BROOKLYN, NEW

YORK, ASSIGNOR TO FORD INSTRUMENT COMPANY, INC, OF LONG ISLAND CITY, NEW YORK, A CORPORATION OF NEW YORK TRANSMITTER Application filed May 24,

This invention relates to transmitters of a type suited for installation at a source of information, and adapted to be set selectively so that information and instructions may be accurately and expeditiously furnished to those conducting operations at relatively remote points and dependent upon such imparted knowledge for eliicient action. A transmitter of this character may, be installed in the plotting room of a Warship, and have electrical circuits running from it to various locations aboard ship, such as to different guns.

()tiice-rs in the plotting room, controlling a naval action, are thus enabled to set up in the instrument and thereby transmit, for example, the range in yards and the deflection in mils, and also commands in connection with the transmitted information. Assurance of the accuracy of important transmitted in formation is thus provided, so that the receiver may encounter no doubt as to the values upon which he is to depend.

The particular nature of the invention as well as other objects and advantages thereof will appear more clearly from a descripti on of a preferred embodiment as shown in the accompanying drawings inwhich,

Fig. 1 is a front elevation of a transmitter embodying the present invention;

Fig, 2 is a plan view thereof; Fig. 3 IS a plan view wlth the cover removed, showing the arrangement of the dials and co-operating units;

Fig. is a sectional View normal to the top face of the transmitter, being taken on the line 4l-t of Fig. 3 and showing the range switch units;

Fig. 5 is a similar View, but is taken on line 5-5 of Fig. 3 and shows the deflection switch units;

Fig. 6 is a plan view of one of the switch units;

Fig. 7 is a vertical section therethrough, taken on the line 77 of Fig. 6;

Figs. 8, 9 and are horizontal sections through the switch shown in Fig. 7, respectiv-ely taken on the successively lower lines 88, 99 and 1010'of the last mentioned 1.924. Serial No. 715,767.

of the commutator drum and the co-acting brushes and electrical connections;

Fig. 18 is a horizontal section through the comnmtator drum, on the line 13-13 of Fig. 7;

Fig. 14 is another such section through the drum, taken along the line 1414 of Fig. 7;

Fig. 15 is a horizontal section, on the line 5--15 of Fig. 7 showing an associated pair of slip rings;

Fig. 16 is a vertical section through one of the brushes adapted to co-operate with one of the slip rings carried by the commutator drum;

Fig. 17 is a side elevation of the switch unit shown in Fig. 7, the operating handle and parts immediately associated therewith being omitted;

Fig. 18 is a wiring diagram, showing one of the switch units in circuit with an electrical energizing means and with a device under the control of the switch;

Figs. 19, 20, 21, and 22 are diagrammatic views at successive stages of the rotation of the drum of one of the switch units through.

its passage from one transmitting position to the next;

Fig. 23 is a fragmentary vertical section taken on the line 2323 of Fig. 2 showing the means for operating the lower level range switches;

Fig. 24 is a section taken on the line 2424, of Fig. 25 normal to the dial of the latter figure, and showing the yielding gear train; Fig. 25 is a section taken on line 2525 of Fig. 24*, being viewed at a right angle to the sectional plane of the latter Figure; and

Fig. 26 is a section on the line 26-26 of Fig. 23 and shows the centralizing device associated with switch there illustrated.

Referring now to the drawings, and particularly to Figs. 1 and 2, 1 represents a hollow pedestal upon which is mounted a range and deflection transmitter having an outer casing 2 inclined at an angle to present its upper face 'foreasy reading by an observer. Entering and leaving the pedestal 1 through its base are incoming and return cables 3 and 4, respectively, from which the conductors run to various connection members, indicated as mounted upon the terminal blocks 5.

Also within the pedestal 1 are mounted fuseswhich protect the electrical apparatus.

Anauto transformer'ti is supported in the upper'portion of the pedestal. Leads from the auto transformer are carried to switch unit devices hereinafter fully referred to.

As shown in Fig. 1, and somewhat better in Fig.2, provision is made of a plurality of range setting handles 8, 9, 10 and 11, each of which is operated to set up a desired numeral in a window individual thereto. Such windows are shown in Fig. 2 at 12, 13, 14, and 15. In Fig. 2, these windows respectively contain the numerals 2, 4, 6, and 80, thereby denoting a range of 24,680yards.

straight line at the back of the instrument.-

Com arin Fi s. 2 and" 3 it will be noted that p e a the numerals 2, 4, 6 and 8 are to be found at permanently mounted plate 27.

the rear-most portions of the referredto dials, the cipher representing the unit column of the range designation being. engraved upon a Plate 27, as shown in Fig. 4, is carried by an arm 28 mounted on a stem 29'of a hollow'casing associated with the end switch unit.

the deflection reading through the window 18 in the top of the instrument. As seen in Fig. .3 the numerals that appear in the tens and hundreds columns, however, are to be found on the dial of a large switch unit, the construction of which is similar to all the other switch units,'but which has a greater number of steps, to wit, 0 to 19 inclusive. A smaller companion switch unit, bears numerals runlng from 0 to 9 for the units column inclusive. As shown 1n Fig. 3, where the dials of the deflection switch units become approximately tangent, the numerals on both dials co-operate to give a reading of 123, which accordingly appears at the window 18 in Fig. 2. Y

Since, as has been stated, all f the switch units are similar in character, it will suffice to describe one of them. Therefore, looking at the right hand switch unit in Fig. 3 of the deflection switches, and observing the same in the direction of the arrow A, a. plan of the same will be found in Fig. 6. A head 30 of an operating handle, also seen in Fig. 7, is pinned to a shaft 31 which projects downwardly through ,a sleeve or bushing 32 and Similar switch units are employedto give has at its bottom a flange portion 33 from which depend a pair of driving pins 34. These pins are shown in dotted lines in Fig. 6 and in section in Fig. 3. latter figure and in Fig. 7 the pins 34 enter apertures in the disc-like portion 35 of a plunger 36, which plunger has a vertically arranged slot 37 through which passes a pin 38 that is anchored in the side wallsof the shaft 31. A spring 39 is seated in a cavity in shaft 31, bearing against an internal shoulder of the latter and a shoulder on the plunger 36. Consequently, the disc-like portion 35 of the plunger is normally forced downwardly, and downwardly projecting driving pins 40 rivet-ed thereto enter elongate-d slots 41 in an intermediate driving disc 42, well shown in Figs. 7 and 9. r j i Intermed'ate disc 42 is similarly provided with downwardly projecting pins 43 that eX- tend between jaw members 44 and 45 of acentralizing device, best shown in Fig. 10, as

considered in connection with Fig. 7. Jaws are provided on opposite sides of the pivotal point of the jaw members 44 and 45, each pair of bars bearing against one of the pins with pressure derived from the centralizing spring 46. When operated, the head 30 under normal circumstances will, through the various discs and. ins exert a turnin effort on the sides of the jaws, the spring 46 ordinarilytending to make the movement a definite one. Referring again to Figs. 7 and 9, it will be seen that there are elliptical cavities 47 in the underside of the intermediate disc member 42, into which project upwardly extending pins 48, the lower ends of pins 48 being driven into a hub 49 to which is secured, as by screws, the dial 50.

Riveted or otherwise secured to the underside of hub 49 is a detent wheel 51, which as As shown in the V I its best seen in Fig. 11, has teeth providing suitable notchesfor rollers 52 carried by oscillatorylevers 53, pivotally mounted upon studs 54 and having rearwardly extending short arms 55between which extends a spring 7 device normally spreading the short arms 55 apart. 7 7

' It will be observed in Fig. 6 that there are twelve steps designated on the dial 50, two

of which are marked fNo signal, and that Fig. 11 shows the detent 51 to be provided with a corresponding number of notches for the reception of the rollers 52. When the rollers 52' are seated in the notches of the detent 51, a numeral or No signal designation on the dial 50 contributes to the reading through the window associated with the dial, and also signifies that there is an establishment of a circuitbetween the unit switch in question and a remote device responding to the control of such switch.

,Without the construction illustrated in Figs; 8 to 10' inclusive, there is liable to be a tendency for imperfect transmission, which however is entirely avoided by the mechanism shown in these figures. Such danger is due to the possible tendency of the roller to sticlcat the apex of the tooth over which it is riding, when the switch is being turned-from one designation to another. As shown in Figs. 7 and 8, when handle 3 is turned, there is a consequent movement of shaft 31, pins 34 and the downwardly projecting pins which results in the turning of the intermediate disc member 42. Pins 43 secured to disc 42 consequently turn and cause one of the jaw members, 44 for example, to accompany them, but the inertia of the switch mechanism causes the pins 48 that project into the ellpitical cavities 47 to remain stationary for the time being. Thus, additional energy is stored in the spring 46 until such time as the walls of the elliptical cavities engage the pins 48 whereupon there is a positive drive of the pins and consequently of the hub 49 and its dial 50. The additional energy so stored in the spring 46 causes the rollers 52, seen in Fig. 11, to snap past the apices of the teeth of the detent 51, whereupon the spring 46 immediately restores the driving mechanism to the position shown in Fig. 10, which is its normal arrangement.

The spring device, which, as shown in Fig. 11, presses apart the short arms of the levers 53, auses the rollers 2 to immediately set themselves into the successive notches pre sented upon actuation of the head 30 of the switch unit. As. shown in Fig. 11, the spring device has semi-spherical ends 56, which are seated in tangential bearing seats near the ends of the short arms 55' of the levers. The device comprises telescopic members 57 and 58 normally spread apart by a spring 59 hearing against shoulders on these members near the spherical ends thereof.

At their outer ends, the levers 53 are pro vided with insulating blocks 60 which extend toward and bear against spring pressed auxiliary switch arms 61, which arms are provided with contact members 62 adapted to bear against other contact members 63, which in turn are carried by other spring influenced switch arms 64. The spring pressure on the arms 61 and 64 of each switch is such as to urge them toward each other, each spring arm 64 being, however, limited to slight movement by insulating posts 65 and 66 on opposite sides thereof.

When the detent disc is turned through the agency of head 30, the rollers 52 are moved outwardly to the apices of the respective teeth over which they are traveling, the insulatingblocks 60 thereupon pressing the switch arms 61 away from switch arms 64, thereby effecting the separation of the contacts 62 and 63 of both auxiliary switches and open ing of the circuit in which the switches are located, and making circuit changes later set forth. The rollers 52 having passed the auxiliary apices of the teeth which force them outward ly are swung inwardly, whereupon theswitch arms 61 and 64 resume their positions; wherein the contacts. 62 and 63 re-establish closures in their respective circuit The switch arms 61 and 64 are pivotally mount on rrins 67, which are each riveted, or otherwise secured, to the lower leg of a bifurcated terminal lug 68, as shown in Figs. 7, 11 and 17. The upper end of pivot pins 67 project into the upper leg of bifurcated termin al member, but are not necessarily secured thereto. The terminal lugs 68 are. mounted in pairs at each side of the switch unit upon an inverted T-shaped insulating member 69, which in turn is fastened or in any other suitable way, by means of screws to a metallic plate 69 on the upper side of the commutator drum frame of the switch unit. Insulating sheets 70 underlie the T-shaped members and extend between the metallic portions of the auxiliary switches comprising the arms 61 and 64 and the adjacent levers 53, whereby compactness of the unit is rendered possible. Terminal clips 71 are fastened to the terminal lugs 68 and conductors lead therefrom to appropriate places in the electrical circuits.

The hub 49, with its dial 50, as best seen in Fig. 7, is secured to the driving shaft 72 of the commutator drum of the switch unit. The driving shaft 72 extends through a metallic sleeve 73 of the drum structure, sleeve 7 3 being provided with an annular flange 74 in its upper portion. To this flange is secured the drum structure proper, the latter being built up of annular sections, the central and uppermost insulation sections being secured together as by bolts 75, shown in Fig. 7. Underneath the central section is a bottom insulating section, through which pass tap screws 76 that also pass through an underlying metallic annular plate 77, screws 76 binding the drum structure as a whole to the flange 74 of the sleeve 73. Mounted upon the insulating drum are current-carrying slip rings 78 and 79 at the upper side of the commutator drum, and 80 and 81 on the lower side of such drum. The slip rings may be secured, as shown in Figs. 7 and 15, by screws 82 that pass through tie blocks 83 of in sulating material, except at those points where the slip rings are connected to the drum contact segments 84, 85, 86 and 87. At these places, the connection is such as is shown in Fig. 7, where a pin 88 is seen to be riveted into a slip ring 79 and to pass through the tie blocks 83, the upper insulating drum section 89 and through the metallic drum segment contact 84, to which the opposite end of the pin is riveted. As seen in Fig. 13, the drum segment contacts 84 and 85, and also 86 and 87, are maintained in peculiar relation, being separated by an air gap and an insulating block 90 in each contactassembly. The readerlying the shoulder formed by the diameter brushes 91, 91

commutator drumsupporting frame.

son for such construction will be plain hereinafter.

It has been made clear that the dial has twelvepositions, as shownin Fig.6,and that the detent 51has a corresponding number of positions, and reference to Fig. 12 will disclose that there are a similar number of 91 etc., carried by brush holders 92 mounted on posts 93 annularly arranged around the commutator drum, the brushes being spring pressed to bear against the periphery of such drum. Leading from thebrushes 91 are electrical conductors 94, which extend to suitable clips screwed to terminal lugs 95 mounted on an insulating plate 96 which forms the bottom member of the These conductors 94 are-diagrammatically shown in Fig. 18 and will be later referred to in the description of the circuits.

In Fig. 17 one of the brush posts 93 is in broken-away form to. show the manner of supporting. It will be seen that the upper end of the post 93 projects into a recess in the upper insulating plate of the drum-supporting frame and that the post for a short distance below the upper plate is of square cross-section. The post is cylindrical where it passes through the brush spring 98 and is reduced in diameter where it passes through the brush, its lower end being seated in a recess in the bottom insulating plate 96. Screws pass through the upperand lower commutator drum frame insulating plates 97 and 96,

respectively, and are threaded into the opposite ends of brush posts 93, the heads of the screws being imbedded in the plates. An insulating layer or sheet 99 is interposed between the upper insulating plate 97 and the metallic plate 69 thereabove to insulate the screw heads from such metallic plate. Each brush 91, 91 etc, has its upper surface unreduction in the cylindrical portion of its post 93,- and surrounding the lower end of such post is a sleeve 100 which acts as a spacer between the bottom insulating plate 96 and the brush and forms a seat for the latter.

Secured in the bottom insulating plate 96 of the commutator drum frame, and also in the upper insulating plate 97, and so as to project through the superposed metallic plate 69, are lower and upper ball bearings 101 and 102, respectively, for the mounting of the shaft 72 of the commutator switch drum. As shown in Fig.7, the central metallic sleeve 73 of the drum is provided in its lower portion with a pin 103 having a cylindrical portion seated in the sleeve and a squared portion 103 that projectsinto a notch in the annular member 77 located on the bottom of the switch drum, whereby in conjunciton with the clamping screws 76 and the flange 74 a well established drive betics and it will therefore be is formed.

To be seen in Fig. 11 in full lines and in dotted lines in Fig. 12, are resilient brushes positioned to bear upon the current-carrying slip rings 78, 7 9, 80. and 81. Some of these brush assemblies are double and others are single, but all possess the same characterissuflicient to describe the brush illustrated in Fig. 16 as indicative of the form of these brushes generally. In that figure, is shown a plate 104 apertured for the passage of a metallic sleeve 105 having a flange to bear against an internal shoulder of the upper insulating plate 97 of the switch drum frame. The upper end of sleeve 105 is threaded both externally and internally, the external thread receiving a washer 106 and nut 107, which, when screwed home, cooperates with the flange on sleeve 105 to clamp such sleeve in position. Screwed into the upper end of sleeve 105 is a plug 108, under the head of which is a suitable washer 109, and extending through a central aperture in the plug is a plunger rod 110. Carried on the lower end of rod110 a brush 111 which bears upon one of the slip rings, such as ring 79. Interposed between the brush 111 and the underside of the plug 108 is a spring 112, which presses the brush firmly against the slip ring, assuring good electrical connection at all times. Fastened to the upper end of rod 110 externally of the plug 108 is an electrical conductor 113 which extends to a terminal washer 114 held in place by a screw 115 and a lock washer under the head thereof. In Fig. 11,

it is seen that a suitable wire clip 116 is also description of this figure may be regarded as,

applicable to any of the switch units of this applies to the larger switch unit which is used to give the numerals for the tens and hundreds columns of the deflection reading,

the larger switch simply having a greater number of steps, and consequent electrical,

result in the inclusion in the circuit contype incorporated-in the instrument. This trolled by such switch unit of different lengths of the auto-transformer windingaccordingly, voltages of various values suited to harmonize with .the individual numerals oi he switch unit dial are carried from. 2c portion of the wintthe a:ate-transformer 6, through the c unit, to the stator winding S of an indicator 1 locat d at a more or less remote point, as at a gun. Hence, as the dial is: turned so. that one number replaces another under the win dow, as, say, at 18 in F ig- 2, a voltage of different value is set up. in the circuit that 111- cludes the stator winding S of the indicator I. This indicator is of a type well known in the art, and it is suiiicient to say that as the volta 'o is changed inits stator winding, there is a consequent responseand adjustmentv of the rotor R, with. a resultant angular displacement of the rotor. No. diiliculty will be enperienced in understanding that this angular displacement may be communicated to a dial corresponding to; dial of the switch unit in the transmitter, so that the reading in that instrument and that given by the indicator 1 will be the same.

In Fig. 18, a circuit is shown estab-lished for one position of the dial of one of the switch units of the transmitter, such circuit being'extended to the stator and rotor windings of the indicator I associated with that switch iuiit. This circuit goes from the winding of; transform-er 6 by lead/122 and one of the conductors 94 to the brush 91 and drum se 'ment 86, continuing through a current conductor to the outer lower slip ring 80. The circuit then goes by brushes 111, which bear on the ring 80, and by conductors 125 and 126 to the nowclosed right hand switch members. 64 and 61, proceeding therefrom by conductors 127 and 128 to the stator winding S of the indicator 1.. From the winding S the circuit goes by conductors 129- and 130, through the at present closed left hand switch members 61 and 64, and by conductors 131 and 132 to the brushes 111 which bear upon the outer upper slip ring 78'. From hence the circuit extends by a current-conductor to drum segment 84, then passing by brush 91 and conductor 133 and tap lead 124 to another part oi the winding of the auto-transformer 6.

It is, therefore, apparent that the stator winding S is energized by current from a portion of the auto-transformer winding, and that rotor winding R of the indicator 1 responds accordingly. If, now, the drum of the switch unit be rotatedcloclrwise, so that the drum contact segments 86 and 84 engage brushes 91 and 91 respectively, the circuit will extend from the winding of the autotransformer 6 by lead 123 and one of the conductors 94 to the brush 91, then by drum segment 86. to the lower slip ring 80, by brushes 111 and conductors 125 and 126 tov the right hand switch members 64 and 61. As before, the circuit continues by conductors. 127 and 128, through the stator winding S of the indicator I, and by 'conductors 129 and 130 to the left hand switchniembers 61 and 64. Thence the circuit goes by conductors 1311 and 132, upper brushes 111, upper slip ring 78 and by a current-conductorto drum contact segment 84. From here the circuit runs by brush- 91 conductor 134 and lead 123. to the auto-trans former winling. A zero position is thus set up, when no part of the auto-transformer is in circuit.

In each instance the rotor of the indicator I is excited by the alternating current which gasses from the ai-ito-transformer. through the switch unit to it. The rotor so excited in duces. in the stator windings z-ilternating currents, whose strength and phase relations to each other depend upon the setting ofthe unit switch, which selectively includes variousportions of the autortransformer winding in circuit, both for the two settings traced and the remaining possible settings.

Figs. 19 to 22inclusive, in conjunction. with Fig. 18, show diagrammatically the 210610115016 the commutator drumof the switch unit resulting from turning the dial 50 of that unit from one circuit-makingand indicating position to the next. The arrangement is such as to avoid injurious sparking as the drum con tacts 8485 and 86-87? engage and leave the brushes 91, 91 91 91 etc.

Fig. 19 showsa circu-it-establishing condi tion, such as is illustrated in Fig. 18, wherein the resistance 136. diverts the current'to di not it from drum contact 86to conductor 126, to the right hand auxiliary switch members 64 and 61 and by conduct-or 127 to conductor 128 that leads to the stator winding S: of the indicator I. Similarly, resistance 142 causes the current path extending by conductor 129 from the stator winding S to be deflected through the conductor 130 and the left hand auxiliary switch members 61 and 64, and to continue by conductors 131 and 132-to the drum contact 84.

It has been shown that, when the dial 550 of the switch unit is turned from: one position to the next, the notched detent wheel 5-1, illustrated in Fig. 11, forces the rollers-52 outwardly and also the levers 53 which carry them. The blocks of insulation afii xed' to the levers 53 thereupon separate the arms 61 of both auxiliary switches from their aseo'ciate arms 64, as diagrammatically indicated in Fig.20. Brush 91 is still engaged with contact 86', but the current from the lat ter passes by conductor 135 through the resistance 136 to conductor 128, which runs to the indicator stator winding S. From winding S the circuit extends by conductor 129 to a junction point 129. With the parts in the positions shown in Fig. 20, the current-path divides, one branch passing through resistance 142 and by conductor 141 to the drum contact 84. The other branch goes by way of resistance 144 and conductor 143 to the brushes 91* and 91",respectively,

drum contact 85. Brush 91? effects a junction of the two branches just traced, and the inclusion of the resistance in the circuit pre vents injurious sparking as contact 85 moves into engagement with brush 91 which in Fig.

7 20 is shown to engage both contact segments inclusion of the resistances 136, 138, 142 andv 144 in circuit, combined with the opened auxiliary switches comprising members 64, removes ing.

In Fig. 22, contacts 86 and 85 have entirely disengaged brushes 91 and 91 respectively, and contacts 86 and 84 are in engagement with brushes 91 and 91", which effects a new connection of the indicator winding S with the winding of the auto-transformer 6, whereby the winding S of the indicator I is affected by an altered electro-motive-force, in consequence of which the indicator corresponds to that readableupon the dial of the switch unit. The switch unit drum, however, to be properly positioned for this is turned slightly more than is shown in Fig. 22,until contacts 86 and 84 occupy the same relative position to that they did to brushes 91 and 91 respectively in Fig. 19. The auxiliary switch members 61 and 64 are now in closed positions,.and the resistances 136,138, 142 and 144 are not in circuit."

The range and deflection transmitter hereinbefore described is located ata central stain the plotting'room of a war tion, as say, vessel. Bymeansof thecables '3 and 4 this instrument is placed in circuit with a plurality of information-receiving instruments,

1 such as the indicators I previously referred to.

These indicators are positioned at. stations remote to the central station or plotting room,

as has been explained, being placed at the guns, stations of observation and where the 7 information furnished by the range and deflection transmitter is needed. r

Fig. 2 shows that the handles 8, 9, 10 and 11 have been manipulated to operatethe irange switch units, whereby their dials 23 to 26inolusive are positioned, as shown in F g 3, to give the range reading observed in Fig.2, which reading shows the range to be 61 and the danger of deleterious spark the gun fire effective.

17, seen in spectively, switch units, whereby the dials thereof co-act to give-a deflection reading of 123 mils. This 24680 yards. Eachof the range switch units being similar to that illustrated in Figs. 6 to 22 inclusive, it will be readily comprehended that its commutator drum has been rotated to place the contacts 84 and 86 of the drum into engagement with such of the annularl disposed brushes 91, 91 91 91 etc., as wi l correspond to a circuit establishment The value of this circuit is. electrically synonymous to the numerical value on the dial which is readable through the window. From Fig. 18, it is apparent that the circuit so set up includes another instrument-the indicator cluded in the circuit. The indicator dial (not1shown) movable in response to and in proportion to the movement of the rotor R of the indicator accordingly shows at the latter instrument a reading corresponding to that of the unit switch of the transmitter with which it is in circuit.

Therefore, when the range switch units of the transmitter are set so that their dials cooperate, as in Fig. 3, to give the range reading shown in Fig. 2, the indicator I, or any plurality of such indicators as are in circuit,

will show the same range reading as does the transmitter. 1

Thus, the sight-setter at any gun, for example, which is furnished with an indicator, is enabled to set the gun sight in the usual manner for a gun elevation in conformity with the range in yards as disclosed by the indicator.

This step in aiming the gun being taken care of, as explained, it becomes necessary to provide for the proper gun-train to render The gun-train, in addition toethe'major training of the gun, includes gun-train for deflection, which is due to a number of factors, such as the relative speed of own ship and the target, windage,

and the time of flight and drift of the pro-' j ectile. From information readily vobtainable in the plotting room, the handles 16 and Fig. 2, are operated to actuate, re-

the larger and smaller deflection information is transmitted to the indicator or .indicators I in the manner just set forth with respect to the range, and, therefore, requires no repetitional description.

Upon receipt of the deflection at his indicator,.th'e sight setter sets the gun-sight in accordance with the primary gun-train combined with thegun train for the deflection angle. The gun being now set for both gun elevation and gun-train, including the deflection, it is aimed at the target and is ready to be fired. Any alterations in the range and deflection due to altering conditions are immediately transmitted from the transmitter in the plotting room to the indicator at the gun, and. the latter is constantly main.- tained aimed for hitting the target.

rrom the foregoing, it is evident that I have made an invention, wherein the various steps of setting and: controlling one or a plurality ot guns are subject to centralized control under the direction of these highly skilled in the art of warfare, yet simultaneously furnishing information in familiar terms tothose remotely located and to whom the physical translation of the orders from the central command station is intrusted. liurthcrmore, it is plain that, with the use of theinrention, the controlling oiilcers and the men carrying out their orders, both, suitably and highly trained for their respective duties, have their activities linked through e'lcctrormechanical means which serve in. the i-snterestoi? eiliciency to unify the work of the officers and men- I claim:

1. In a device of the character described, a. brush, a contact member to cooperate therewithcomprising two conductors separated by insulating material, and means comiected with said separated conductors to allow full current to tlow when the brush is in complete engagement and to reduce the current when the brush is in partial engagement.

2. In a device of the character described, a plurality of brushes arranged a; regular intervals and a member having twocontacts for selective engagement with pairs of said brushes, each of said contacts comprising two; parts separated by insulating material.

3- In a device of the character described, a; plurality of brushes arranged at regular intervals and a member having two contacts for selective engagement with pairs of said brushes, each of said contacts comprising a narrow part and a broad part separated by insulating, material.

t. In a device of the character d scribed U l 7 a plurality of brushes arranged regular n, tervals and a member raving two contacts for brushes, each of said contacts con'r n'ising a narrow part and a broad part septu -ted by insulating material, said parts being arranged in opposite order in the two contacts.

5; In a device of the character described, a plurality of brushes arranged at regular intervals and member having two contacts for selective engagement with pairs of said brushes, each of said contacts comprising two parts separated by insulating material and having an air-gap between the ends with which the brushes contact.

6. In a device of the character described, a plurality of brushes arranged at regular intervals, a menber having two contacts for selective engagement with pairs of said two parts separated by insulating material and means connected with both partsof each contact to control the current at times of circuit making and breaking.

7. The combination with a brush, of'a current conducting contact device to engage said brush in moving past the same and com.- prising two contact portions separated by insulating material, and means to allow full current to flow wh'enthe brush is incomplete engagement and to reduce the current when the brush is in partial engagement.

8'. The combination with a brush, of a ou-rrent conducting contact device toengage-said brush in moving past the same and compristwo. contact portions separated by insulating material and having an airgap between them adjacent their brush-ei-igaging surfaces, and means to allow full current to How only when the brush is: in complete contact with the contact device.

9. In a signal transmitter, a plurality of stationary brushes, a rotatable element coacting with said brushes to form a switch andhaving two contacts for selective engagement with pairs of said brushes, a detent device to position the switch in circuit cl os ing positions, and resistance devices controlled by said detent device to prevent sparking at the brushes.

10. In a signal transmitter, two relatively rotatable elements, one of said elements having a plurality of brushes arranged inan arc of a circle and the other having pair of contact devices for selective engagement cuit, a station aryelement comprising a brush,

a rotatable member having; a contact device to engage said brush H1 moving past the same,

said contact device comprising two insulated parts for successive engagement by said brush, a resistance connection between one part of said contact device and said circuit, a resistance and a switch in parallel connecting the second part of the contact device with the circuit, and means effective after the brush has completed the circuit through the resistance connected to the first part and, then through the resistance connected to the second part to close said switch and then to open the switch before the contact between the brush and the second element is broken.

12. In a device of the character described, a plurality ofbrushes arranged in an arc of a circle, a rotatable member having two contacts to engage pairs of said brushes, and means for positioning and detaining said? ro tatable member in operative: position With re- 63 brushes, each of said contacts comprising spect to any pair of brushes, comprising a toothed wheel connected with said rotatable element and spring pressed detent members to engage said wheel.

14:. In a device of the character described,

a plurality of brushes arranged in an arc of a circle, a rotatable member having two contacts to engage pairs of said brushes, means for positioning and detaining said rotatable member in operative position with respect to any pair of brushes, comprising a toothed wheel connected with said rotatable element and spring pressed detent members to engage said wheel, and anti-sparking devices, one for each contact, operated by said detent members, each of said anti-sparking devices comprising two pivoted contact members spring pressed toward each other and means operated by the corresponding detent mem-, ber to move one of said contacts away from the other. I

, 15. In a device ofthe character described, a plurality of brushes arranged in an arc of a circle, a rotatable member having two con tacts to engage pairs of said brushes, means y tatable shaft for the swltch, a member fixed for positioning and detaining said rotatable member inoperative position with respect'to any pair of brushes, comprising a toothed wheel connected with said rotatable element and spring pressed detent membersto engage said wheel, and anti-sparking devices, one

'for each contact, operated by said detent members, each of said anti-sparking devices comprising two pivoted contact members spring pressed toward each other, .means operated by; the corresponding detent memberQto move one of'said contacts away from the other and astop to limit the movement of the other and thereby permit" such separa tion. 1

16. In a signaltransmitter, a plurality of 1 stationary brushes, a rotatable element coacting with said brushes to form a switch and havlng two contacts for selective engagement with pairs of sald brushes, a detent devlce to "position the switch in circuit closing posisaid plates, brushes on said posts, conductors connecting said brushes wlth terminals on.

one of said plates, and a rotatable member mounted in said plates and havingconductors to cooperate with said brushes.

18. In a switch, two parallel plates of in sulating material, metal posts connecting said plates, brushes on said posts, conductors connecting said posts with terminals on one of said plates, and a rotatable member mounted in said plates and having contacts to cooperate with said brushes, and slip rings electrically connected with said contacts to cooperate therewith in circuit closing and opening.

19. In a switch, a plurality of brushes arranged in a circular arc, and a rotatable member having two contact devices for selective engagement with pairs of said brushes, each of said contact devices comprising two conductors separated by insulating material, a pair of contact rings connected with the conductors of one of said contact devices, and a pair of contact rings connected with the conductors of the other contact device.

20. In a switch, a plurality of brushes arranged in a circular arc; a rotatable member having two contact devices for selective engagement with pairs of said brushes, each of said contact devices comprising two conductors separated by insulating material, a pair of contact rings connected with the conductors of one of said contact devices, and a pair of contact rings connected with the conductors of the other contact device; and means, including a circuit breaker for each contact device, to prevent sparking.

21. In a device of the class described, a roon said shaft and having upwardly projecting pins, twolevers pivoted on said shaft and crossed so as to engage said pins on opposite sides of the shaft, a spring connecting the levers at one side of the shaft to urge the arms of the lever toward said pins, a member pivoted'on said shaft and having two pins projecting downwardly between the arms of said levers and having openings therein HARRY S. MARSH.

CERTIFICATE OF CORRECTIQN.

Patent No. 1,795,341. Granted March 10, 1931, to

HARRY S. MARSH.

It is hereby certified that error appears in the printed specification oi the above numbered patent requiring correction as follows: Page 3, line 16, for the misspelled word ellpitical" read elliptical; page 4, line 64, for "conjunciten" read conjunction; same page, line 109, for "from" read ierm; page 7, line 63, claim 6, for "member" read member; page 8, line 7, claim 13, for brusites" read brush, and line 13, for "device" read devices; same page, line 19, ciaim 14, for "brushes read brush; strike out lines 101 to 116, comprising claim 21; and that the said Letters Patent should be read with these corrections therein that the same may coniorm to the record of the case in the Patent Office.

Signed and sealed this 21st day of April, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

